73 lightwin tuning problem

[Retrogrouch]

I have been working on this motor for a while. So far, I have replace the mounting bolts on the gear case, put in a new impeller, and a carb kit. I used the ogininal shop manual to do the work.

The moter will start ( after some fine ajusting of the choke) an soulds ok, but stops when I either move in the choke, or increase the throtle. It will restart after I dry the plugs. I check the float twice, and used fresh fuel.

Any Ideas?
Thanks

 

[ezeke]

Re: 73 lightwin tuning problem

What HP? Are you running with Champion J6C plugs at .030?

If it stops when you release the choke, it indicates that it is not getting enough gasoline without the choke. Try increasing the fuel air mix (turn low speed needle counter-clockwise in small increments). Did you remove the needles and check for flow though the carburetors?

 

[Retrogrouch]

Re: 73 lightwin tuning problem

Thenks for the fast response!
The motor is a 4hp weedless. I think the plugs are in order. When I rebuild the carb, I blew air throught all the pasages.
When I ajusted the low speed needle, I did not hear any change in the rpm sounds the motor was putting out. ( Also, the pull cord just snaped, so anyfurther attemps at starting are going to be a little while in coming)

I will report back when I get the started sorted!!!

 

[1946Zephyr]

Re: 73 lightwin tuning problem

Yea, it sounds like your high speed circuit is plugged. Nice little motor. I have one just like it in my shed, that I just rebuilt for a guy.

 

[Retrogrouch]

Re: 73 lightwin tuning problem

Here is the long time in coming update (sorry to those whom ofered advise previously):
I fixed the cord, so the non stop pulling can continue.
Now The motor would not start at all. ( things are going down hill)

The motor is a 4106d weedless 4 hp

So here goes. The coils were cracked and I could see burn marks, so I replaced them, as well as the condensers. One set of points was poorly alined, so I changed them as well. The end result is that I have strong spark on a motor that still won't start.
I went through the carb again, and it looks clean. The reed valves look good. I changed the fuel twice. There is fuel coming out of the fuel pump, and when I pull the high speed needle out after a few pulls, gas drains out of the bowl.
The compression is great. Both cylinders are well over 100.

I took the cover off the exhaust port that is underneath the the starter cord, and found that the gasket was leaking coolant (water) into the exhaust chamber next to the cylinders. There was emulsified oil in there. There was also a hint of it on the plugs
It was late, and the parts store was not open, so I made a temp. gasket of 411. No Dice. It will fire some times, for a second then die.

My new plan.
Get the real gasket for that exhaust port.
Is it possible that the timing is so messed up that it won't start? Is it possible that this emulsified oil in the exhaust is getting into the cylinder, and stoppingg combustion? where can I look to see if there is water getting into the intake side?

Thanks for your time

 

[F_R]

Re: 73 lightwin tuning problem

It is a 1971, not 1973. Nevertheless, if it is getting water into the cylinders, therein lies your problem. Water puts out fires. The common water intrusion routes are the exhaust cover gasket, head gasket, and powerhead base gasket. Most likely the head gasket.

Also, not to pee on your parade, but if it has been ingesting water, the motor may be seriously damaged. That also will keep it from running.

 

[Retrogrouch]

Re: 73 (that really a 71) lightwin tuning (big) problem

Re: 73 (that really a 71) lightwin tuning (big) problem

OMG parts bill $175 and climbing.
Is there any tests that I can do, before I dump in even more money? I know the compression is good. If the water was only coming in on the exhaust side of things, can the moisture work it's way back into the combustion chamber, and the intake manifolds? What kind of problems would the water cause? Are we talking bearings and bushings?

Thanks for your Input